Decoupling between Shockley partials and stacking faults strengthens multiprincipal element alloys

Area of Science:

• Materials Science
• Mechanical Engineering
• Computational Materials Science

Background:

• Dislocations are crucial for understanding the mechanical behavior of structural materials.
• Multoprincipal element alloys (MPEAs) show high yield stresses, but their underlying mechanisms are not fully understood.

Purpose of the Study:

• To elucidate the mechanistic origins of the excellent mechanical properties in MPEAs.
• To investigate the relationship between dislocations, Shockley partials, and stacking faults in MPEAs.

Main Methods:

• Multiscale study combining density functional theory (DFT).
• Atomistic simulations.
• High-resolution microscopy.

Main Results:

• The excellent mechanical properties of MPEAs stem from diverse origins.
• Strengthening effects from Shockley partials and stacking faults can be decoupled in MPEAs.
• This decoupling challenges the conventional understanding linking low stacking fault energies with wide partial dislocations.

Conclusions:

• The study clarifies the mechanistic origins of strengthening effects in MPEAs.
• Provides a foundation for developing physics-informed predictive models for materials design.
• Offers new insights into the mechanical behavior of advanced alloys.